In U.S. patent application Ser. No.07/667,494 filed Mar. 11, 1991 and entitled "Optical Multilayer Structures for Harmonic Laser Emission", now U.S. Pat. No. 5,111,466 by R. J. F. Normandin et al, it was disclosed that two counter-propagating lights which are contained in an optical waveguide along a single dimension can interact and form a second harmonic optical signal which is emitted from the optical waveguide in a direction different from the single dimension, and thus can be detected outside the waveguide. The disclosed waveguide is formed of layers of semiconductor material having different indices of refraction. The thicknesses of the layers and their periodicity determine the bandwidth, and the relative wavelengths of the two input signals determine the angles of emission of the harmonic signal.
When the two guided fundamental wavelengths are identical, oppositely propagating and travelling in the same colinear one dimensional path, the radiated harmonic signal is observed in a direction perpendicular to the surface of the waveguide. When the two oppositely propagating optical signals are of differing wavelength, wavevector addition rules coupled with energy conservation rules dictate the angle of emission as well as the sum harmonic wavelength.